The present invention relates generally to a safety setback lock or release for ordnance devices and more particularly to a device for arming the fuze of an ordnance missile only after a predetermined period of sustained acceleration such as occurs, for example, in the discharge of a rocket.
In ordnance missiles, which commonly carry explosive charges, it is desirable that the missiles remain safe or "unarmed" until they have been fired. This unarmed state insures maximum safety of the personnel using the missile and enables the explosive to cause damage to the target. Various means have been used to secure this result. For example, rotating missiles have been equipped with arming mechanisms which are responsive to the centrifugal forces developed when the missile is fired. Non-rotating missiles, such as mortar shells, certain classes of rockets and the like, have been equipped with arming mechanisms which are responsive to the forces of setback, which occurs when the missile is launched. However, in U.S. Pat. No. 2,625,881, there is shown such an arming mechanism which includes a particular double element release which is responsive to sustained acceleration only. The double element release mechanism includes a pair of spring mass systems wherein the masses are a pair of concentric sliding cylinders.